Problem: 8 crayons cost $9.52. Which equation would help determine the cost of 12 crayons?
There are several equations that could help determine the cost, each with a slightly different approach. If we let $x$ represent the cost of 12 crayons, we have the following proportion: $\dfrac{x}{12}$ We have to pay $9.52 for 8 crayons, and that can be written as a proportion: $\dfrac{\$9.52}{8}$ Since the price per crayon stays the same, these two proportions are equivalent. $\dfrac{x}{12} = \dfrac{\$9.52}{8}$